@@ -389,6 +389,18 @@ config MCP4725
To compile this driver as a module, choose M here: the module
will be called mcp4725.
+config MCP4728
+ tristate "MCP4728 DAC driver"
+ depends on I2C
+ help
+ Say Y here if you want to build a driver for the Microchip
+ MCP4728 quad channel, 12-bit digital-to-analog converter (DAC)
+ with I2C interface.
+
+ To compile this driver as a module, choose M here: the module
+ will be called mcp4728.
+
+
config MCP4922
tristate "MCP4902, MCP4912, MCP4922 DAC driver"
depends on SPI
@@ -41,6 +41,7 @@ obj-$(CONFIG_MAX517) += max517.o
obj-$(CONFIG_MAX5522) += max5522.o
obj-$(CONFIG_MAX5821) += max5821.o
obj-$(CONFIG_MCP4725) += mcp4725.o
+obj-$(CONFIG_MCP4728) += mcp4728.o
obj-$(CONFIG_MCP4922) += mcp4922.o
obj-$(CONFIG_STM32_DAC_CORE) += stm32-dac-core.o
obj-$(CONFIG_STM32_DAC) += stm32-dac.o
new file mode 100644
@@ -0,0 +1,635 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Support for Microchip MCP4728
+ *
+ * Copyright (C) 2023 Andrea Collamati <andrea.collamati@gmail.com>
+ *
+ * Based on mcp4725 by Peter Meerwald <pmeerw@pmeerw.net>
+ *
+ * Driver for the Microchip I2C 12-bit digital-to-analog quad channels
+ * converter (DAC).
+ *
+ * (7-bit I2C slave address 0x60, the three LSBs can be configured in
+ * hardware)
+ */
+
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/err.h>
+#include <linux/delay.h>
+#include <linux/regulator/consumer.h>
+#include <linux/mod_devicetable.h>
+#include <linux/property.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+
+#define MCP4728_DRV_NAME "mcp4728"
+
+#define MCP4728_RESOLUTION 12
+#define MCP4728_N_CHANNELS 4
+
+#define MCP4728_CMD_POS 3
+#define MCP4728_CMD_UDAC_POS 0
+#define MCP4728_CMD_CH_SEL_POS 1
+
+#define MCP4728_CMD_VREF_MASK 0x80
+#define MCP4728_CMD_VREF_POS 7
+
+#define MCP4728_CMD_PDMODE_MASK 0x60
+#define MCP4728_CMD_PDMODE_POS 5
+
+#define MCP4728_CMD_GAIN_MASK 0x10
+#define MCP4728_CMD_GAIN_POS 4
+
+#define MCP4728_MW_CMD 0x08 // Multiwrite Command
+#define MCP4728_SW_CMD 0x0A // Sequential Write Command (include eeprom)
+
+#define MCP4728_READ_RESPONSE_LEN (MCP4728_N_CHANNELS * 3 * 2)
+#define MCP4728_WRITE_EEPROM_LEN (1 + MCP4728_N_CHANNELS * 2)
+
+enum vref_mode {
+ MCP4728_VREF_EXTERNAL_VDD = 0,
+ MCP4728_VRED_INTERNAL_2048mV = 1,
+};
+
+enum gain_mode {
+ MCP4728_GAIN_X1 = 0,
+ MCP4728_GAIN_X2 = 1,
+};
+
+enum iio_powerdown_mode {
+ MCP4728_IIO_1K,
+ MCP4728_IIO_100K,
+ MCP4728_IIO_500K,
+};
+
+struct mcp4728_channel_data {
+ enum vref_mode ref_mode;
+ enum iio_powerdown_mode pd_mode;
+ enum gain_mode g_mode;
+ u16 dac_value;
+};
+
+struct mcp4728_data {
+ struct i2c_client *client;
+ struct regulator *vdd_reg;
+ bool powerdown;
+ struct mcp4728_channel_data channel_data[MCP4728_N_CHANNELS];
+};
+
+#define MCP4728_CHAN(chan) { \
+ .type = IIO_VOLTAGE, \
+ .output = 1, \
+ .indexed = 1, \
+ .channel = chan, \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
+ .ext_info = mcp4728_ext_info, \
+}
+
+static int mcp4728_suspend(struct device *dev);
+static int mcp4728_resume(struct device *dev);
+
+static ssize_t mcp4728_store_eeprom(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t len)
+{
+ struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+ struct mcp4728_data *data = iio_priv(indio_dev);
+ u8 outbuf[MCP4728_WRITE_EEPROM_LEN];
+ int tries = 20;
+ u8 inbuf[3];
+ bool state;
+ int ret;
+ unsigned int i;
+
+ ret = kstrtobool(buf, &state);
+ if (ret < 0)
+ return ret;
+
+ if (!state)
+ return 0;
+
+ outbuf[0] = MCP4728_SW_CMD << MCP4728_CMD_POS; // Command ID
+
+ for (i = 0; i < MCP4728_N_CHANNELS; i++) {
+ struct mcp4728_channel_data *ch = &data->channel_data[i];
+ int offset = 1 + i * 2;
+
+ outbuf[offset] = ch->ref_mode << MCP4728_CMD_VREF_POS;
+ if (data->powerdown) {
+ u8 mcp4728_pd_mode = ch->pd_mode + 1;
+
+ outbuf[offset] |= mcp4728_pd_mode
+ << MCP4728_CMD_PDMODE_POS;
+ }
+
+ outbuf[offset] |= ch->g_mode << MCP4728_CMD_GAIN_POS;
+ outbuf[offset] |= ch->dac_value >> 8;
+ outbuf[offset + 1] = ch->dac_value & 0xff;
+ }
+
+ ret = i2c_master_send(data->client, outbuf, MCP4728_WRITE_EEPROM_LEN);
+ if (ret < 0)
+ return ret;
+ else if (ret != MCP4728_WRITE_EEPROM_LEN)
+ return -EIO;
+
+ /* wait RDY signal for write complete, takes up to 50ms */
+ while (tries--) {
+ msleep(20);
+ ret = i2c_master_recv(data->client, inbuf, 3);
+ if (ret < 0)
+ return ret;
+ else if (ret != 3)
+ return -EIO;
+
+ if (inbuf[0] & 0x80) // check RDY flag
+ break;
+ }
+
+ if (tries < 0) {
+ dev_err(&data->client->dev, "%s failed, incomplete\n",
+ __func__);
+ return -EIO;
+ }
+ return len;
+}
+
+static IIO_DEVICE_ATTR(store_eeprom, 0200, NULL, mcp4728_store_eeprom, 0);
+
+static struct attribute *mcp4728_attributes[] = {
+ &iio_dev_attr_store_eeprom.dev_attr.attr,
+ NULL,
+};
+
+static const struct attribute_group mcp4728_attribute_group = {
+ .attrs = mcp4728_attributes,
+};
+
+enum chip_id {
+ MCP4728,
+};
+
+static int mcp4728_program_channel_cfg(int channel, struct iio_dev *indio_dev)
+{
+ struct mcp4728_data *data = iio_priv(indio_dev);
+ struct mcp4728_channel_data *ch = &data->channel_data[channel];
+ u8 outbuf[3];
+ int ret;
+
+ outbuf[0] = MCP4728_MW_CMD << MCP4728_CMD_POS; // Command ID
+ outbuf[0] |= channel << MCP4728_CMD_CH_SEL_POS; // Channel Selector
+ outbuf[0] |= 0; // UDAC = 0
+
+ outbuf[1] = ch->ref_mode << MCP4728_CMD_VREF_POS;
+
+ if (data->powerdown) {
+ u8 mcp4728_pd_mode = ch->pd_mode + 1;
+
+ outbuf[1] |= mcp4728_pd_mode << MCP4728_CMD_PDMODE_POS;
+ }
+
+ outbuf[1] |= ch->g_mode << MCP4728_CMD_GAIN_POS;
+ outbuf[1] |= ch->dac_value >> 8;
+ outbuf[2] = ch->dac_value & 0xff;
+
+ ret = i2c_master_send(data->client, outbuf, 3);
+ if (ret < 0)
+ return ret;
+ else if (ret != 3)
+ return -EIO;
+ else
+ return 0;
+}
+
+// powerdown mode
+static const char *const mcp4728_powerdown_modes[] = { "1kohm_to_gnd",
+ "100kohm_to_gnd",
+ "500kohm_to_gnd" };
+
+static int mcp4728_get_powerdown_mode(struct iio_dev *indio_dev,
+ const struct iio_chan_spec *chan)
+{
+ struct mcp4728_data *data = iio_priv(indio_dev);
+
+ return data->channel_data[chan->channel].pd_mode;
+}
+
+static int mcp4728_set_powerdown_mode(struct iio_dev *indio_dev,
+ const struct iio_chan_spec *chan,
+ unsigned int mode)
+{
+ struct mcp4728_data *data = iio_priv(indio_dev);
+
+ data->channel_data[chan->channel].pd_mode = mode;
+
+ return 0;
+}
+
+static ssize_t mcp4728_read_powerdown(struct iio_dev *indio_dev,
+ uintptr_t private,
+ const struct iio_chan_spec *chan,
+ char *buf)
+{
+ struct mcp4728_data *data = iio_priv(indio_dev);
+
+ return sysfs_emit(buf, "%d\n", data->powerdown);
+}
+
+static ssize_t mcp4728_write_powerdown(struct iio_dev *indio_dev,
+ uintptr_t private,
+ const struct iio_chan_spec *chan,
+ const char *buf, size_t len)
+{
+ struct mcp4728_data *data = iio_priv(indio_dev);
+ bool state;
+ int ret;
+
+ ret = kstrtobool(buf, &state);
+ if (ret)
+ return ret;
+
+ if (state)
+ ret = mcp4728_suspend(&data->client->dev);
+ else
+ ret = mcp4728_resume(&data->client->dev);
+
+ if (ret < 0)
+ return ret;
+
+ return len;
+}
+
+static const struct iio_enum mcp4728_powerdown_mode_enum = {
+ .items = mcp4728_powerdown_modes,
+ .num_items = ARRAY_SIZE(mcp4728_powerdown_modes),
+ .get = mcp4728_get_powerdown_mode,
+ .set = mcp4728_set_powerdown_mode,
+};
+
+// vref mode
+static const char *const mcp4728_vref_modes[] = {
+ "vdd_ext",
+ "internal",
+};
+
+static int mcp4728_get_vref_mode(struct iio_dev *indio_dev,
+ const struct iio_chan_spec *chan)
+{
+ struct mcp4728_data *data = iio_priv(indio_dev);
+
+ return data->channel_data[chan->channel].ref_mode;
+}
+
+static int mcp4728_set_vref_mode(struct iio_dev *indio_dev,
+ const struct iio_chan_spec *chan,
+ unsigned int mode)
+{
+ struct mcp4728_data *data = iio_priv(indio_dev);
+ int ret;
+
+ data->channel_data[chan->channel].ref_mode = mode;
+
+ if (mode == MCP4728_VREF_EXTERNAL_VDD &&
+ data->channel_data[chan->channel].g_mode == MCP4728_GAIN_X2) {
+ dev_warn(&data->client->dev,
+ "CH%d: Gain x2 not effective when vref is vdd, force to x1",
+ chan->channel);
+ data->channel_data[chan->channel].g_mode = MCP4728_GAIN_X1;
+ }
+
+ ret = mcp4728_program_channel_cfg(chan->channel, indio_dev);
+
+ return ret;
+}
+
+static const struct iio_enum mcp4728_vref_mode_enum = {
+ .items = mcp4728_vref_modes,
+ .num_items = ARRAY_SIZE(mcp4728_vref_modes),
+ .get = mcp4728_get_vref_mode,
+ .set = mcp4728_set_vref_mode,
+};
+
+// gain
+static const char *const mcp4728_gain_modes[] = {
+ "x1",
+ "x2",
+};
+
+static int mcp4728_get_gain_mode(struct iio_dev *indio_dev,
+ const struct iio_chan_spec *chan)
+{
+ struct mcp4728_data *data = iio_priv(indio_dev);
+
+ return data->channel_data[chan->channel].g_mode;
+}
+
+static int mcp4728_set_gain_mode(struct iio_dev *indio_dev,
+ const struct iio_chan_spec *chan,
+ unsigned int mode)
+{
+ struct mcp4728_data *data = iio_priv(indio_dev);
+ int ret;
+
+ if (mode == MCP4728_GAIN_X2 &&
+ data->channel_data[chan->channel].ref_mode ==
+ MCP4728_VREF_EXTERNAL_VDD) {
+ dev_err(&data->client->dev,
+ "CH%d: Gain x2 not effective when vref is vdd",
+ chan->channel);
+ return -EINVAL;
+ }
+
+ data->channel_data[chan->channel].g_mode = mode;
+
+ ret = mcp4728_program_channel_cfg(chan->channel, indio_dev);
+
+ return ret;
+}
+
+static const struct iio_enum mcp4728_gain_mode_enum = {
+ .items = mcp4728_gain_modes,
+ .num_items = ARRAY_SIZE(mcp4728_gain_modes),
+ .get = mcp4728_get_gain_mode,
+ .set = mcp4728_set_gain_mode,
+};
+
+static const struct iio_chan_spec_ext_info mcp4728_ext_info[] = {
+ {
+ .name = "powerdown",
+ .read = mcp4728_read_powerdown,
+ .write = mcp4728_write_powerdown,
+ .shared = IIO_SEPARATE,
+ },
+ IIO_ENUM("powerdown_mode", IIO_SEPARATE, &mcp4728_powerdown_mode_enum),
+ IIO_ENUM_AVAILABLE("powerdown_mode", IIO_SHARED_BY_TYPE,
+ &mcp4728_powerdown_mode_enum),
+ IIO_ENUM("vref_mode", IIO_SEPARATE, &mcp4728_vref_mode_enum),
+ IIO_ENUM_AVAILABLE("vref_mode", IIO_SHARED_BY_TYPE,
+ &mcp4728_vref_mode_enum),
+ IIO_ENUM("gain_mode", IIO_SEPARATE, &mcp4728_gain_mode_enum),
+ IIO_ENUM_AVAILABLE("gain_mode", IIO_SHARED_BY_TYPE,
+ &mcp4728_gain_mode_enum),
+ {},
+};
+
+static const struct iio_chan_spec mcp4728_channels[MCP4728_N_CHANNELS] = {
+ MCP4728_CHAN(0),
+ MCP4728_CHAN(1),
+ MCP4728_CHAN(2),
+ MCP4728_CHAN(3),
+};
+
+static int mcp4728_full_scale_mV(u32 *full_scale_mV, int channel,
+ struct mcp4728_data *data)
+{
+ int ret;
+
+ if (data->channel_data[channel].ref_mode == MCP4728_VREF_EXTERNAL_VDD)
+ ret = regulator_get_voltage(data->vdd_reg);
+ else
+ ret = 2048000;
+
+ if (ret < 0)
+ return ret;
+
+ if (ret == 0)
+ return -EINVAL;
+
+ *full_scale_mV = ret / 1000;
+ return 0;
+}
+
+static u32 mcp4728_raw_to_mV(u32 raw, int channel, struct mcp4728_data *data)
+{
+ int ret;
+ u32 full_scale_mV;
+
+ ret = mcp4728_full_scale_mV(&full_scale_mV, channel, data);
+ if (ret)
+ return ret;
+
+ return (((raw + 1) * full_scale_mV) >> MCP4728_RESOLUTION);
+}
+
+static int mcp4728_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan, int *val,
+ int *val2, long mask)
+{
+ struct mcp4728_data *data = iio_priv(indio_dev);
+ int ret;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ *val = data->channel_data[chan->channel].dac_value;
+ return IIO_VAL_INT;
+ case IIO_CHAN_INFO_SCALE:
+ if (data->channel_data[chan->channel].ref_mode ==
+ MCP4728_VREF_EXTERNAL_VDD)
+ ret = regulator_get_voltage(data->vdd_reg);
+ else
+ ret = 2048000;
+
+ if (ret < 0)
+ return ret;
+
+ *val = ret / 1000;
+ *val2 = MCP4728_RESOLUTION;
+ return IIO_VAL_FRACTIONAL_LOG2;
+ }
+ return -EINVAL;
+}
+
+static int mcp4728_write_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan, int val,
+ int val2, long mask)
+{
+ struct mcp4728_data *data = iio_priv(indio_dev);
+ int ret;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ if (val < 0 || val > GENMASK(MCP4728_RESOLUTION - 1, 0))
+ return -EINVAL;
+ data->channel_data[chan->channel].dac_value = val;
+ ret = mcp4728_program_channel_cfg(chan->channel, indio_dev);
+ break;
+ default:
+ ret = -EINVAL;
+ break;
+ }
+
+ return ret;
+}
+
+static const struct iio_info mcp4728_info = {
+ .read_raw = mcp4728_read_raw,
+ .write_raw = mcp4728_write_raw,
+ .attrs = &mcp4728_attribute_group,
+};
+
+static int mcp4728_suspend(struct device *dev)
+{
+ struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
+ struct mcp4728_data *data = iio_priv(indio_dev);
+ int err = 0;
+ unsigned int i;
+
+ data->powerdown = true;
+
+ for (i = 0; i < MCP4728_N_CHANNELS; i++) {
+ int ret = mcp4728_program_channel_cfg(i, indio_dev);
+
+ if (ret)
+ err = ret;
+ }
+ return err;
+}
+
+static int mcp4728_resume(struct device *dev)
+{
+ struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
+ struct mcp4728_data *data = iio_priv(indio_dev);
+ int err = 0;
+ unsigned int i;
+
+ data->powerdown = false;
+
+ for (i = 0; i < MCP4728_N_CHANNELS; i++) {
+ int ret = mcp4728_program_channel_cfg(i, indio_dev);
+
+ if (ret)
+ err = ret;
+ }
+ return err;
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(mcp4728_pm_ops, mcp4728_suspend,
+ mcp4728_resume);
+
+static int mcp4728_init_channels_data(struct mcp4728_data *data)
+{
+ u8 inbuf[MCP4728_READ_RESPONSE_LEN];
+ int ret;
+ unsigned int i;
+
+ ret = i2c_master_recv(data->client, inbuf, MCP4728_READ_RESPONSE_LEN);
+ if (ret < 0) {
+ dev_err(&data->client->dev,
+ "failed to read mcp4728 conf. Err=%d\n", ret);
+ return ret;
+ } else if (ret != MCP4728_READ_RESPONSE_LEN) {
+ dev_err(&data->client->dev,
+ "failed to read mcp4728 conf. Wrong Response Len ret=%d\n",
+ ret);
+ return -EIO;
+ }
+
+ for (i = 0; i < MCP4728_N_CHANNELS; i++) {
+ struct mcp4728_channel_data *ch = &data->channel_data[i];
+ u8 r2 = inbuf[i * 6 + 1];
+ u8 r3 = inbuf[i * 6 + 2];
+ u32 dac_mv;
+
+ ch->dac_value = (r2 & 0x0F) << 8 | r3;
+ ch->ref_mode = (r2 & MCP4728_CMD_VREF_MASK) >> MCP4728_CMD_VREF_POS;
+ ch->pd_mode = (r2 & MCP4728_CMD_PDMODE_MASK) >> MCP4728_CMD_PDMODE_POS;
+ ch->g_mode = (r2 & MCP4728_CMD_GAIN_MASK) >> MCP4728_CMD_GAIN_POS;
+
+ if (ch->g_mode == MCP4728_GAIN_X2 && ch->ref_mode == MCP4728_VREF_EXTERNAL_VDD)
+ dev_warn(&data->client->dev,
+ "CH%d: Gain x2 not effective when vref is vdd",
+ i);
+
+ dac_mv = mcp4728_raw_to_mV(ch->dac_value, i, data);
+ dev_info(&data->client->dev,
+ "CH%d: Voltage=%dmV VRef=%d PowerDown=%d Gain=%d\n", i,
+ dac_mv, ch->ref_mode, ch->pd_mode, ch->g_mode);
+ }
+
+ return 0;
+}
+
+static int mcp4728_probe(struct i2c_client *client)
+{
+ const struct i2c_device_id *id = i2c_client_get_device_id(client);
+ struct mcp4728_data *data;
+ struct iio_dev *indio_dev;
+ int err;
+
+ indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
+ if (!indio_dev)
+ return -ENOMEM;
+
+ data = iio_priv(indio_dev);
+ i2c_set_clientdata(client, indio_dev);
+ data->client = client;
+
+ data->vdd_reg = devm_regulator_get(&client->dev, "vdd");
+ if (IS_ERR(data->vdd_reg))
+ return PTR_ERR(data->vdd_reg);
+
+ err = regulator_enable(data->vdd_reg);
+ if (err)
+ goto err_disable_vdd_reg;
+
+ err = mcp4728_init_channels_data(data);
+ if (err) {
+ dev_err(&client->dev,
+ "failed to read mcp4728 current configuration\n");
+ goto err_disable_vdd_reg;
+ }
+
+ indio_dev->name = id->name;
+ indio_dev->info = &mcp4728_info;
+ indio_dev->channels = mcp4728_channels;
+ indio_dev->num_channels = MCP4728_N_CHANNELS;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+
+ err = iio_device_register(indio_dev);
+ if (err)
+ goto err_disable_vdd_reg;
+
+ return 0;
+
+err_disable_vdd_reg:
+ regulator_disable(data->vdd_reg);
+
+ return err;
+}
+
+static void mcp4728_remove(struct i2c_client *client)
+{
+ struct iio_dev *indio_dev = i2c_get_clientdata(client);
+ struct mcp4728_data *data = iio_priv(indio_dev);
+
+ iio_device_unregister(indio_dev);
+ regulator_disable(data->vdd_reg);
+}
+
+static const struct i2c_device_id mcp4728_id[] = { { "mcp4728", MCP4728 }, {} };
+MODULE_DEVICE_TABLE(i2c, mcp4728_id);
+
+static const struct of_device_id mcp4728_of_match[] = {
+ { .compatible = "microchip,mcp4728" },
+ {}
+};
+MODULE_DEVICE_TABLE(of, mcp4728_of_match);
+
+static struct i2c_driver mcp4728_driver = {
+ .driver = {
+ .name = MCP4728_DRV_NAME,
+ .of_match_table = mcp4728_of_match,
+ .pm = pm_sleep_ptr(&mcp4728_pm_ops),
+ },
+ .probe = mcp4728_probe,
+ .remove = mcp4728_remove,
+ .id_table = mcp4728_id,
+};
+module_i2c_driver(mcp4728_driver);
+
+MODULE_AUTHOR("Andrea Collamati <andrea.collamati@gmail.com>");
+MODULE_DESCRIPTION("MCP4728 12-bit DAC");
+MODULE_LICENSE("GPL");
mcp4728 is a 12-bit quad channel DAC with I2C interface. support for: * per-channel gain * per-channel power state * per-channel power down mode control * per-channel vref selection internal/vdd * store current state to on-chip EEPROM Signed-off-by: Andrea Collamati <andrea.collamati@gmail.com> --- drivers/iio/dac/Kconfig | 12 + drivers/iio/dac/Makefile | 1 + drivers/iio/dac/mcp4728.c | 635 ++++++++++++++++++++++++++++++++++++++ 3 files changed, 648 insertions(+) create mode 100644 drivers/iio/dac/mcp4728.c